-- All bot-like behaviour (response to commands, etc)

bot = {}

function bot:Initialize(IRC, Prefix)
    self._irc = IRC
    self._prefix = Prefix
    self._meme = "alexa, "
    self._commands = {}

    hook.Add('irc.Message', 'bot.OnChannelMessage', function(Username, Channel, Message)
        local Success, Error = pcall(function()
            self:OnChannelMessage(Username, Channel, Message)
        end)
        if not Success then
            Channel:Say("Whoops! Error when executing OnChannelMessage: " .. Error)
        end
    end)
    self:AddCommand('eval-core', -1, function(Username, Channel, String)
        local Function, Message = loadstring(String)
        if not Function then
            Channel:Say("Parse error: " .. Message)
            return
        end
        local Status, Message = pcall(Function)
        if not Status then
            Channel:Say("Error -> " .. Message)
        else
            Channel:Say("OK -> " .. tostring(Message))
        end
    end, "Runs a Lua command in the bot context.", 100)
end

function bot:OnChannelMessage(Username, Channel, Message)
    local String
    if Message:sub(1,#self._prefix) == self._prefix then
        String = Message:sub(#self._prefix + 1)
    elseif Message:lower():sub(1, #self._meme) == self._meme then
        String = Message:sub(#self._meme + 1)
    else
        return
    end

    local Command
    local Arguments = {}
    for Part in String:gmatch("%S+") do
        if Command == nil then
            Command = Part
        else
            Arguments[#Arguments + 1] = Part
        end
    end

    if Command == nil then
    	Channel:Say("No command given.")
    	return
    end
    if not self._commands[Command] then
        local FellBack =  hook.Call("bot.UnknownCommand", Username, Channel, Command, Arguments)
        if not FellBack then
            Channel:Say("Unknown command '" .. Command .. "'.")
        end
    else
        local CommandData = self._commands[Command]
        if #Arguments ~= CommandData.Arguments and CommandData.Arguments ~= -1 then
            Channel:Say(string.format("Command '%s' expects '%i' arguments, got '%i'.",
                Command, CommandData.Arguments, #Arguments))
        else
            -- -1 means we want a raw string
            if CommandData.Arguments == -1 then
                if #Arguments < 1 then
                    Channel:Say("Please provide an argument.")
                    return
                end
                Arguments = { table.concat(Arguments, ' ') }
            end
            local RequiredAccess = CommandData.Access
            if RequiredAccess == 0 then
                CommandData.Callback(Username, Channel, unpack(Arguments))
                return
            end
            local Account = hook.Call("auth.GetAccount", irc, Username)
            if not Account then
                Channel:Say("Please identify with NickServ.")
                return
            end
            local UserAccess = hook.Call("auth.GetLevel", Channel, Account)
            if not UserAccess then
                Channel:Say("Could not run command because auth backend is missing.")
                return
            end
            if UserAccess >= RequiredAccess then
                CommandData.Callback(Username, Channel, unpack(Arguments))
            else
                Channel:Say(string.format("Insufficient access level (%i required).", RequiredAccess))
            end
        end
    end
end

function bot:AddCommand(Name, Arguments, Callback, Help, Access)
    local Command = {}
    Command.Callback = Callback
    Command.Access = Access or 0
    Command.Help = Help or "No help available."
    Command.Arguments = Arguments
    self._commands[Name] = Command
end

function bot:RemoveCommand(Name)
    self._commands[Name] = nil
end